We discussed this before elsewhere, but handling may suffer, if you put a Prolink Fork into an early CBX. In order to maintain the same wheelbase, Honda changed the offset in the triple tree to compensate for the increased rake in the 81/82 models. This will cause your trail to shrink significantly in a 79/80. Steering may become too quick and straight line stability is lacking.

I have not doen a wheel conversion. You may have to play with the spacers in the rear, no biggie. the fornt, I agree, may be a different story as the rotors and calipers are also different. Maybe someone alse has done it?